The ciliary epithelium, composed of two cell layers, is both a barrier and an entranceway to the interior of the eye for substances from the blood stream. The Na+/K+ ATPase enzyme is the major active transporter of ions across the plasma membranes of the ciliary process. Regulation of this enzyme could produce significant regulation of intraocular pressure. With the sodium/potassium ATPase, the cellular carbonic anhydrase, which regulates anions, could form a core regulatory group, as they jointly maintain the levels of the ions most vitally involved in aqueous humor production. Newly-recognized regulatory factors in cellular function include receptor coupling to intracellular processes through G proteins, and phosphorylation and dephosphorylation of specific target proteins. Using the ciliary process of the rabbit eye in in vitro assays, analyzed using PAGE, protein transfer, autoradiography, and specific antibodies for sodium/potassium ATPase and carbonic anhydrase, the ciliary process will be investigated for 1) regulation by possible phosphorylation and dephosphorylation of the enzyme subunits, and 2) specific molecular mechanisms involving other proteins, by which that regulation is effected. Both enzymes will be examined, in an attempt to establish possible coordinate regulation. Also, drugs and other substances known to effect intraocular pressure will be used to search for and identify coordinate responses. The long-term goal is, through better understanding of the fundamental processes underlying aqueous humor formation, to add to the arsenal of treatments available for glaucoma. I am applying for this award as a non-clinical investigator coming into vision research for the first time, and as a recently trained basic scientist.